Field of the Invention
The invention relates to a method of manufacturing a control flap, which is disposed in particular in an intake duct of an internal combustion engine.
International Patent Application WO 96/07022 discloses a control flap which has a shaft and an elongated configuration along an axis of rotation of the shaft. The control flap is disposed in an opening between two inlet pipes of an intake device and is mounted so as to be pivotable. The inlet pipes branch off from a first manifold and lead into inlets of cylinders of the internal combustion engine. If the control flap is pivoted in such a way that the opening is closed, the effective length of the inlet pipes, that is, the length over which the gas column in the inlet pipe oscillates, corresponds to the length of the inlet pipes from the first manifold to he inlets of the cylinders. If the control flap is pivoted in such a way that the opening is opened, the effective length of the inlet pipes corresponds to the distance from the opening up to the inlets of the cylinders. Depending on measured values of the operating variables of the internal combustion engine, one of the two effective lengths of the inlet pipes is set. Thus the charging of the cylinders can be improved and the maximum torque can therefore be increased.
Provided at the opening are bearing collars, against which the control flap comes to bear when it is pivoted in such a way that the opening is closed.
U.S. Pat. No. 3,724,812 discloses a control flap which has a plate with an encircling groove at its margins. Slots, which communicate with the groove, are made in the plate. A seal is inserted into the groove and the slots.
It is accordingly an object of the invention to provide a method of manufacturing a control flap that overcomes the above-mentioned disadvantages of the prior art methods of this general type, which is simple to manufacture and reliable.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method of manufacturing a control flap, which includes: providing a shaft; disposing a first sleeve and a second sleeve onto the shaft at a predetermined axial distance apart from each other and radially pressing the first sleeve and the second sleeve; forming a vane body having at least one aperture by encapsulating the shaft between the first sleeve and the second sleeve with a thermoplastic; and encapsulating the vane body with a sealing compound and forming a sealing lip at margins on the vane body from the sealing compound.
The method according to the invention is distinguished by the fact that the shaft is encapsulated with a thermoplastic in such a way that the vane body is formed. The vane body is configured in such a way that it has at least one aperture. A sealing compound, with which the vane body is encapsulated, penetrates into the aperture, so that there is a positive-locking connection between the sealing compound and the vane body.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method of manufacturing a control flap, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.